Heretofore, as liquid-sealed antivibration devices used for motor vehicles, there has been known a liquid-sealed antivibration device which comprises a first attaching member, a cylindrical second attaching member, an antivibration base body connecting these first attaching member and second attaching member and constituted by a rubber-like elastic body, a diaphragm defining a liquid-sealed chamber between itself and the antivibration base body and constituted by a rubber-like elastic body, a partition member dividing the liquid-sealed chamber, and an orifice making communication between the liquid-sealed chambers divided by the partition member.
Patent Literature 1 discloses a technology wherein an outer edge part of a diaphragm is vulcanization-bonded (connected) to a cylindrical diaphragm attachment (outer fitting member) having a larger inside diameter than the outside diameter of a partition member, wherein the diaphragm attachment is externally fitted with the diaphragm interposed between itself and the partition member, and wherein a second attaching member is subjected to a diameter reduction process.